Presently known mechanical chilling devices for cargo containers are usually fixed to and pass through the front bulkhead of such containers, road vehicles or railway wagon bodies. Such chilling devices are driven either by an internal combustion engine forming part of the device, or by an electric motor supplied with current generated by, e.g. the engine of a road vehicle or an axle mounted generator in railway equipment. With containers, road vehicles and wagons employing eutectic beams or plates for cooling purposes the plates or beams are usually mounted on the inside of the walls or roof of the container. Eutectic beams are frozen to operational temperatures by either an externally mounted refrigeration compressor, driven by an internal combustion engine, or by an external source of electric power which is disconnected when freezing is complete and the container or vehicle is about to enter service. In either instance, the vehicle mounted equipment occupies valuable cargo space especially when the container or vehicle is to be used for the carriage of goods not requiring a controlled atmosphere. In addition, such equipment tends to cool the entire atmosphere within the cargo compartment rather than just that surrounding the goods requiring refrigeration. In accordance with the present invention, there is provided a portable chilling unit which substantially reduces the problems associated with the above-mentioned devices.